1. Field of the Invention
This invention relates to a reflection-type bandpass filter for use in ultra-wideband (UWB) wireless data communication.
2. Description of the Related Art
This invention relates to a reflection-type bandpass filter for use in ultra-wideband (hereafter “UWB”) wireless data communication. By using this UWB reflection-type bandpass filter, U.S. Federal Communications Commission requirements for spectrum masks can be satisfied.
As technology of the prior art related to this invention, for example, the technology disclosed in the following references 1 through 10 is known.    Reference 1: Specification of U.S. Pat. No. 2,411,555    Reference 2: Japanese Unexamined Patent Application No. 56-64501    Reference 3: Japanese Unexamined Patent Application No. 9-172318    Reference 4: Japanese Unexamined Patent Application No. 9-232820    Reference 5: Japanese Unexamined Patent Application No. 10-65402    Reference 6: Japanese Unexamined Patent Application No. 10-242746    Reference 7: Japanese Unexamined Patent Application No. 2000-4108    Reference 8: Japanese Unexamined Patent Application No. 2000-101301    Reference 9: Japanese Unexamined Patent Application No. 2002-43810    Reference 10: A. V. Oppenheim and R. W. Schafer, “Discrete-time signal processing,” pp. 465-478, Prentice Hall, 1998.    Reference 11: G-B. Xiao, K. Yashiro, N. Guan, and S. Ohokawa, “An effective method for designing nonuniformly coupled transmission-line filters,” IEEE Trans. Microwave Theory Tech., vol. 49, pp. 1027-1031, June 2001.    Reference 12: Y. Konishi, “Microwave integrated circuits”, pp. 19-21, Marcel Dekker, 1991
However, the bandpass filters proposed in the prior art may not satisfy the FCC specifications, due to manufacturing tolerances and other reasons.
Further, bandpass filters which use coplanar strips do not use wide ground strips, and so are not suitable for coupling with transmission lines such as slot lines.
This invention was devised in light of the above circumstances, and has as an object the provision of a high-performance UWB reflection-type bandpass filter which has excellent coupling characteristics with transmission lines such as slot lines, and which satisfies FCC specifications.